The present invention generally relates to a manure spreading apparatus and method which incorporate the use of dual longitudinal augers that feed most types of manure into a vertically oriented expeller in order to thereby throw the manure onto an agricultural field or the like. The invention more particularly relates to feeding manure along an elongated auger assembly having a relatively shallow flight profile and to a feed portion of the auger assembly having a relatively deep flight profile for feeding the manure into the expeller. The manure spreader is typically of the type that is pulled by a tractor or the like and that is run from the power take-off (PTO) thereof.
In the field of manure spreading, two objectives have been sought but have been found to be difficult to attain. One of these objectives is to provide manure spreaders and manure spreading procedures that are as versatile as possible, especially regarding the types of manure that can be spread. More specifically, manures vary in composition from those that are predominantly liquid to those that are predominantly semi-solid or solids containing. Furthermore, certain manures have an especially sticky consistency, and they tend to adhere to manure spreader components and surfaces. Manures can also contain fibrous plant and vegetable waste material and debris. Specific debris can include stones, straw and the like. Manures can be characterized as varying in composition from that of a watery slurry to that of a semi-solid mixture. It is desirable that a manure spreader be able to handle any of these types of manures and to have the ability to distribute same evenly across an agricultural field or the like.
Another principal objective of manure spreading is to avoid the difficulty of having the mechanisms become clogged during use and to avoid the somewhat related difficulty of experiencing bridging which is an especially troublesome problem for manures that have a sticky consistency. Such manures tend to clump into a large solid mass that cannot be readily fed by the manure spreader without breaking up the clump or bridge. In the case of manure spreaders having a longitudinal auger near the bottom of the bed of the device, the manure can bridge between the upstanding walls of the device to the extent that the flow of manure into the auger is severely restricted or prevented. Previous attempts to solve this problem have included movement of the auger into the bridged manure in an attempt to break up the bridge.
These objectives are achieved, and these problems are brought under control, by utilizing the apparatus according to the present invention which is capable of handling wide varieties of manures. The invention addresses itself to the bridging problem by an approach that is directed toward substantially preventing the formation of bridges, rather than one which seeks to break bridges that have already been formed or have been partially formed.